1. Field of the Invention
The present invention relates to a wireless network, and, more particularly, to a method of wireless network initialization.
2. Description of the Related Art
Proximity pairing is not supported in the current ZigBee (IEEE 802.15.4) standard. Although Bluetooth v2.1+EDR provides an optional NFC (Near Field Communication) mechanism for proximity pairing, it needs additional hardware support. Thus, Bluetooth v2.1+EDR is most likely of higher cost.
In most wireless networks, it is critical to have a secure and reliable mechanism to set up a network, and to enable new legitimate network devices to join an established network. In most networks with coordinators (masters), a new network device (e.g., slave or peripheral device) needs to register, associate, and authenticate with the coordinators in order to join the network. This process is also broadly referred to as a “pairing” process between the master and the peripheral devices.
For devices with limited human machine interface or healthcare applications targeting senior citizen customers, a “proximity pairing” mechanism provides significant benefit. With proximity pairing, a user can simply power on a peripheral device, and bring the device into close proximity to a master device. The peripheral device and the master device are automatically paired when they are close enough to each other, or after acquiring an optional confirmation from the user.
Almost all of the existing industrial wireless standards have addressed the association/pairing mechanisms with considerable emphasis on the security and privacy issue. However, the proximity pairing mechanism is not broadly available: ZigBee does not have an embedded proximity pairing capability. For Bluetooth, proximity pairing is available only for its latest version Bluetooth v2.1+EDR. However, Bluetooth v2.1+EDR requires NFC (Near Field Communication), which needs additional hardware support. Such additional hardware results in increased cost.
U.S. patent application publication 2008/0227393, entitled “Method and system for pairing of wireless devices using physical presence” by J. Tang, E. Hankey, and E. Stanford, filed on Mar. 14, 2007, and published on Sep. 18, 2008 discloses techniques that facilitate pairing of wireless devices with other wireless devices. According to one embodiment, a pairing process can be secured through use of physical proximity. However, the disclosed techniques require verification of the closeness of the two devices (master and peripheral devices) before the devices can be paired. After the proximity check is successful, the two devices can continue with the normal network operation, such as a regular association/pairing procedure. Such an approach needs to “cut in” the regular pairing process, which involves significant development effort and may introduce security vulnerability. The communication during the proximity check purely relies on the (proprietary) software developer. However, the software developer may not investigate reliability and security of the system to its full extent.
Although the underlying wireless communication mechanisms to pair a peripheral device with a coordinator could be complicated, it is highly desirable to present a simple yet reliable and secure process from the user experience perspective. This is especially true for devices with limited HMI (Human Machine Interface), or consumer and healthcare applications.
In most of the existing wireless standards, there are several parameters to indicate the strength of the link established between two connected devices, such as a master device and a peripheral device. These parameters are either an indication of the received signal strength, RSSI (Received Signal Strength Indicator), or an indication of the link quality, LQI (Link Quality Indicator), which normally considers both received signal strength and the packet success rate over the link. In most of the implementations, these parameters are measured as an average over a period of time.
What is neither disclosed nor suggested by the prior art is a method of implementing proximity pairing between two devices without the high cost and additional hardware required by known methods.